With the increasing number of youth living with severe obesity and the lack of good conservative treatments, it is not surprising that the volume of bariatric surgery performed in adolescents is on the rise.
Now a study by Thomas Inge and colleagues, published in the New England Journal of Medicine, examines the efficacy and safety of bariatric surgery in teens.
The prospective study was conducted in 242 adolescents (mean age 17 y) undergoing Roux-en-Y gastric bypass (161 participants) or sleeve gastrectomy (67) at 5 US centres.
With the caveat that 15% of participants were lost to follow-up and laboratory data was missing in 24% of participants, the authors report that at 3 years, the mean weight had decreased by 27% with remission of type 2 diabetes in 95% of participants who had had the condition at baseline.
Other improvements in health included remission of abnormal kidney function occurred in 86%, remission of prediabetes in 76%, remission of elevated blood pressure in 74%, and remission of dyslipidemia in 66% of those who had these conditions.
On the other hand, surgery was not without risks.: 57% of participants developed iron deficiencies and 13% of participants required at least one additional intraabdominal operation.
Thus, despite significant health benefits and improvement in quality of life, patients do have to be carefully monitored for nutritional deficiencies.
Obviously, 3 years is not a long period in the life of an adolescent and it will certainly take far longer follow-up to determine the durability of these findings.
Also, there remain significant questions about the psychosocial impact that surgery may have (both positive and negative) on the further development of these young participants.
Nevertheless, till we have better conservative treatments for severe obesity it appears that bariatric surgery may well be a viable treatment option for this population.
Now a study by Robert Eckel and colleagues, published in Current Biology, illustrates how sleep deprivation and timing of meals can markedly alter insulin sensitivity.
Studies were conducted in 16 healthy young adults (8w) with normal BMI. Following a week of 9-hr-per-night sleep schedules, subjects were studied in a crossover counterbalanced design with 9-hr-per-night adequate sleep (9-hr) and 5-hr-per-night short sleep duration (5-hr) conditions lasting 5 days each, to simulate a 5-day work week. Sleep was restricted by delaying bedtime and advancing wake time by 2 hr each.
Energy balanced diets continued during baseline, whereas food intake was ad libitum during scheduled wakefulness of 5- and 9-hr conditions.
Overall, the simulated 5-day work week of 5-hr-per-night sleep together with an ad libitum diet resulted in a 20% decrease in oral and intravenous insulin sensitivity, which was compensated for by increased insulin secretion..
These changes persisted for up to 5 days after restoring 9-hr sleep opportunities.
The authors also showed that shifting circadian rhythm resulted in morning wakefulness and eating during the biological night, a factor that may promote weight gain over time.
According to conventional wisdom, beverages with artificial sweeteners should be weight neutral, given that they do not contain calories. However, whether this is true or not remains controversial. Besides the epidemiological evidence suggesting that the consumption of artificially sweetened beverages may be associated with higher body weights, there are also a range of physiological studies suggesting that artificial sweeteners can induce metabolic changes (including changes in taste preferences) that may promote weight gain.
Now, a study by Ameneh Madjd and colleagues from the University of Nottingham, UK, and the Tehran University of Medical Sciences, Iran (where the study was conducted) published in the American Journal of Clinical Nutrition, suggests that replacing ‘diet beverages’ (DBs) with water may not only result in greater weight loss but may also have greater benefits in terms of glucose metabolism.
The study was conduced in 89 women with overweight or obesity who usually consumed DBs in their diet.
Participants were randomized to either replace their DBs with water or continue drinking DBs 5 times/wk after their lunch for 24 wk (DB group) while on a 24-week weight-loss program.
71% of participants completed the trial (32 in the DB group, 30 in the water group).
Over the 24 weeks, the water group lost about 1.2 Kg more than the DB group (mean weight loss of both groups was about 8 Kg).
Improvements in fasting insulin levels, HOMA index and 2-hr post-prandial glucose also tended to be greater in the water than in the DB group.
Thus, the authors conclude that replacement of DBs with water after the main meal may lead to greater weight reduction and more favourable metabolic benefits during a weight-loss program.
As for the possible mechanisms that would account for these findings, the authors speculate based largely on self-reported changes in food intake that the water-drinking group may have been more compliant to the recommended diet and may have marginally reduced their carb intake. There is also the possibility that drinking water (rather than DBs) may support weight loss through other mechanisms.
Overall, I am not sure what to really make of this study. Clearly, being able to replace DBs with water may be beneficial. On the other hand, the more common problem in my practice is dealing with patients who consume larger amounts of sugar-sweetened beverages (SSBs rather than DBs) and I would imagine that if a shift to water is too drastic, DBs may at least be substantially better than continuing on with SSBs for these patients.
As Canada’s national representative in the World Obesity Federation (formerly IASO), the Canadian Obesity Network is proud to co-host the 13th International Congress on Obesity in Vancouver, 1-4 May 2016.
The comprehensive scientific program will span 6 topic areas:
Track 1: From genes to cells
- For example: genetics, metagenomics, epigenetics, regulation of mRNA and non–coding RNA, inflammation, lipids, mitochondria and cellular organelles, stem cells, signal transduction, white, brite and brown adipocytes
Track 2: From cells to integrative biology
- For example: neurobiology, appetite and feeding, energy balance, thermogenesis, inflammation and immunity, adipokines, hormones, circadian rhythms, crosstalk, nutrient sensing, signal transduction, tissue plasticity, fetal programming, metabolism, gut microbiome
Track 3: Determinants, assessments and consequences
- For example: assessment and measurement issues, nutrition, physical activity, modifiable risk behaviours, sleep, DoHAD, gut microbiome, Healthy obese, gender differences, biomarkers, body composition, fat distribution, diabetes, cancer, NAFLD, OSA, cardiovascular disease, osteoarthritis, mental health, stigma
Track 4: Clinical management
- For example: diet, exercise, behaviour therapies, psychology, sleep, VLEDs, pharmacotherapy, multidisciplinary therapy, bariatric surgery, new devices, e-technology, biomarkers, cost effectiveness, health services delivery, equity, personalised medicine
Track 5: Populations and population health
- For example: equity, pre natal and early nutrition, epidemiology, inequalities, marketing, workplace, school, role of industry, social determinants, population assessments, regional and ethnic differences, built environment, food environment, economics
Track 6: Actions, interventions and policies
- For example: health promotion, primary prevention, interventions in different settings, health systems and services, e-technology, marketing, economics (pricing, taxation, distribution, subsidy), environmental issues, government actions, stakeholder and industry issues, ethical issues
Early-bird registration is now open – click here
Abstract submission deadline is November 30, 2015 – click here
For more information including sponsorship and exhibiting at ICO 2016 – click here
I look forward to welcoming you to Vancouver next year.
In the meantime, Novo Nordisk, the maker of liraglutide, is continuing its development of a new GLP-1 analogue semaglutide as a once-weekly injection for the treatment of diabetes and obesity.
Last week the company released topline data from its SUSTAIN 3 study, a phase 3a trial in around 800 patients with type 2 diabetes randomized (open-label) to once-weekly semaglutide 1.0 mg vs. exenatide 2.0 mg (another once weekly GLP-1 analogue) over 56 weeks.
Participants on semaglutide achieved a greater reduction in A1c (1.5% vs. 0.9%; baseline = 8.4%) and weight loss (5.6 kg vs. 1.8 kg; baseline = 96 kg) compared to exenatide.
In general, adverse events (mainly GI-symptoms) were as expected for GLP-1 analogues with a rate of nausea twice as high with semaglutide compared to eventide (22% vs. 11%).
The overall discontinuation rate due to adverse events was slightly higher with semaglutide than eventide but fairly low overall (9.4% vs. 7.2%).
It should be noted that this was a diabetes and not an obesity study – so the almost 6% weight loss is indeed quite impressive (weight loss in studies designed to test drugs for obesity tends to be higher as patients are also advises to change their diet and physical activity).
According to Novo Nordisk, phase 2 dose-ranging trials of semaglutide in obesity could begin as early as next year – certainly an interesting development to watch.
Disclaimer: I have received honoraria as a consultant and speaker from Novo Nordisk